A European city bike with a skirt guard (the large plate covering the top of the rear wheel), and a chain guard below it.

A skirt guard, dress guard or coat guard is a device fitted over the rear wheel of a bicycle to prevent a long skirt, coat or other trailing clothes or luggage catching in the wheel, or in the gap between the rim and the brakes.

Skirt guards are common on bicycles in continental Europe, where the bicycle is commonly ridden in smart-casual or formal clothing; but very uncommon in English speaking countries where many cyclists wear specialised cycling gear. It is often paired with a chain guard to keep the rider's clothing clean. They are often used on utility bicycles.

There are several forms, for instance:

A length of string may be threaded through holes in the rear mudguard, running radially between the mudguard and the rear dropout.

A lightweight metal mesh covering the upper half of the rear wheel.

A fabric mesh or net stretched over the same area.

A flexible canvas secured over the same area.

A solid, rigid metal or plastic plate, which can be smaller than a canvas piece.

Large, solid surfaces have the disadvantage of air resistance, which increases the risk of being blown sideways by gusty sidewinds. Air-permeable designs such as mesh and string provide a more stable ride, but can be more difficult to keep clean. A pair of small plastic sheets gives moderate air resistance and a smooth surface which is easier to keep clean.